Canada Wood Today | The Canada Wood Group

Canadian Wood Central to Energy Efficient Home

Charles Tanaka

By Charles Tanaka

Japan Program Administrator--Canada Tsuga Promotions

May 11, 2011

A closer look at the Ikumu post & beam home.

A residential single detached house was recently completed in Kasuga-Machi, Nerima-Ku, Tokyo and turned over to its owner on May 5, 2011.  The project was designed by Mr. S. Seno, 1st Class Architect and president of Sekkei Atelier K.K. (Architectural Firm).

The project qualifies as a Rank 2 Structural house while at the same time qualifying as a Low Energy Consumption house.  The designer made use of a wide variety of Canadian Structural and Finishing Materials to design and construct the house.  The following are some of the general specification for the house:

Note: dimensions below are small by Canadian Standard but they are representative of a typical Japanese single detached house in a metropolitan area.

Property or Land:42.09 Tsubos (139.16 m2 or apx. 1,500 s.f.)

Structure’s Footprint: 20.96 Tsubos (69.30 m2 or apx. 746 s.f.)

Total Floor Area: 1st Fl:   20.82 Tsubos (68.84 m2 or apx. 741 s.f.)

2nd Fl:  19.81 Tsubos (65.52 m2 or apx. 705 s.f.)

Total: 39.63 Tsubos (131.02 m2 or apx. 1,410 s.f.)

The structure’s frame is typical modern Japanese Post & Beam system sitting on a steel reinforced concrete foundation.  Materials used for the Japanese Post & Beam wood frame structure are as follows:

Sill Plate – “Dodai”: Pressure Treated Hem-Fir (105x105mm)

Upright Posts – “Hashira”: 105x105mm KD Canada Tsuga E120-F330 (3.0 m)

Through Posts – “Toshi-Bashira”: 120x120mm KD Canada Tsuga E120-F330 (6.0 m)

Diagonal Bracing – “Sujikai”: 45x90mm KD Canada Tsuga E120

Spacer Studs – “Mabashira”: 30x105mm KD Sugi (Japanese Cedar)

Horizontal Beam – “Hari or Hirakaku”: 105×150 to 320mm KD D. Fir

Rafters – “Taruki”: 45×45, 45×60, 45×105 etc. KD Canada Tsuga E120

Sheathing: 9mm OSB for exterior walls, 12mm JPZ Plywood for floors, 12mm JPZ Plywood for Roof.

All wood to wood connection points are Dovetailed or T&G reinforced with Metal Connector Hardware (JIS Certified).  None of the Metal Connector Hardware is used in exposed areas.  Traditional complex Japanese Joinery can be seen at exposed wood to wood connection points in certain areas.

In addition to the structural frame where a significant Canadian Content can be found, other Canadian Finishing materials can be readily appreciated throughout the house.  Some of the Canadian products application is as follows:

Exterior Balcony and Deck:                     

  • Western Red Cedar (2×2, 2×4 and 2×6 dimension lumber)

 Main Entrance Door & Side Wall:           

  • V.G., T&G Clear Western Red Cedar Paneling (3/8” or 9mm)

Interior Flooring:                         

  • 3/4 inch Maple, 3 Ply Japanese Sugi Panels for Stair Treads, Hinoki and other Japanese wood used for decorative purposes.

Interior Trim Work, Shoji Screen and Valance Screens  

  • V.G. Clear Hem-Fir (Canada Tsuga), KD V.G. Clear D. Fir and Spruce.  The Built in Table in the Open Kitchen-Dining area is made from purpose selected VG & Color Matched D.Fir and Hem-Fir.

The project took five months to complete having started in late November 2010 and completing just prior to the May Day Week Holiday in early May, 2011.

The house is designed to take advantage of some of the modern electronic gadgetry for convenience as well as natural sunlight for lighting and heating.  The structure is also designed to dissipate built up heat during the hot summer months through carefully designed air ducts and air flow channels.  Heating system also qualifies under the for low energy consumption guidelines.